Name: SEMTECH SC2545
Brand: SEMTECH
SKU: SC2545

Description

Semtech SC2545 High Performance Wide Input Range Dual Synchronous Buck Controller

Part Number

SC2545

Price

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Manufacturer

SEMTECH

Lead Time

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Category

PRODUCTS - S

Specifications

Iout Max

Operating Frequency

100-300 kHz

Package

TSSOP-24; MLPQ-24

Vin(V) max

Vin(V) min

4.5

Vout Min

.75

Features

“Peel off “start up tracking Independent dual-outputs
10V internal regulator for gate driver to deliver high efficiency
24 lead TSSOP and MLPQ packages
Adjustable output voltage down to 0.75V
Flexible power sequencing with enable and powergood output
Full protection: UVLO, OVP and programmable OCP
Fully WEEE and RoHS Compliant
Independent dual-outputs
Low shutdown current (100nA typical)
No need for current sense resistor
Out of phase operation to reduce cost of input capacitor
Programmable switching frequency: 100kHz~300kHz
Synchronous Buck topology with voltage mode control
Wide input voltage range: 4.5V~28V

Datasheet

SC2545-2026074683.pdf

1636 KiB

Download

Extracted Text

SC2545 High Performance Wide Input Range Dual Synchronous Buck Controller POWER MANAGEMENT Description Features Independent dual-outputs The SC2545 is a high performance dual PWM controller. It is designed to convert a wide ranged input voltage down “Peel off “start up trackingIndependent dual-outputs to two independent output rails. The SC2545 support Wide input voltage range: 4.5V~28V “peel off ” tracking for the two outputs at start up which Adjustable output voltage down to 0.75V means the two outputs ramp up together till the one Flexible power sequencing with enable and power with lower output level reaching the regulation. The PWM good output operations of the two channels are 180 degree out of Synchronous Buck topology with voltage mode phase which can greatly reduce the size and the cost of control the input capacitors. Synchronous Buck PWM topology Out of phase operation to reduce cost of input and voltage mode control allow high efficiency operation, capacitor fast transient responses, and flexible component selec- 10V internal regulator for gate driver to deliver high tion for easy designs. A 10V internal linear regulator pro- efficiency vides the bias for the controller, and this voltage is opti- Programmable switching frequency: mized for gate drivers to deliver high efficiency. The power 100kHz~300kHz sequencing is fully supported including independent start up, and power good output. In the shut down mode the Full protection: UVLO, OVP and programmable controller only draws 100nA from the supply. The con- OCP troller also offers full protection features for the condi- No need for current sense resistor tions of under voltage, over voltage, and the over current. Low shutdown current (100nA typical) There is no need for a current sensing resistor because 24 lead TSSOP and MLPQ packages the MOSFET on resistance is used for the sensing Fully WEEE and RoHS Compliant element. The switching frequency is adjustable from 100 Applications kHz to 300 kHz. Two packages TSSOP-24 and MLPQ-24 are offered. Systems with 4.5V~28V input LCDTV and PDPTV Network and telecom systems Typical Application Circuit SC2545 VO1 VIN+ 1 24 VIN AGND VCC 2 23 VCC ROSC 3 22 ENABLE PWGRD EN PWRGD 4 21 FB1 FB2 FB1 FB2 5 20 ERROUT1 ERROUT2 6 19 VIN+ SS1 SS2 VIN+ 7 18 ILIM1 ILIM2 8 17 BST1 BST2 9 16 VO2 VO1 DRVH1 DRVH2 10 15 PHASE1 PHASE2 11 14 DRVL1 DRVL2 FB1 VCC FB2 12 13 PGND PVCC Pinout shown as TSSOP-24. Revision: August 10, 2005 1 www.semtech.com SC2545 POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Parameter Sm ymbol Ms aximu Unit BV ST1,BST2 to PGND 3V 8 bst VV IN to PGND 2V 8 in ILIM1,ILIM2 and ENto PGND VV IN VCC and PVCC to PGND 1V 4 PGND to AGND +V /-0.3 BST1 to PH1, BST2 to PH2,DRVH1 to PH1,DRVH2 to PH2 -V 0.3 to 14 DRVL1,DRVL2 to PGND -V 0.3 to VCC PHASE,DRVLto AGND pulse (100nS),peak voltage -V 3 AllOtherPins to AGND -V 0.3 to VCC o ST torage Temperature Range -60 to +150 C STG o JunctionTemperature T -40 to +150 C J Lead Temperature (Soldering)10 Sec forTSSOP-24 o LT ead Temperature (IRReflow)forMLPQ-24 260 C LEAD ThermalResistance Junctionto Case o TSSOP-24 θ 23 C/W JC MLP-24 2 ThermalResistance Junctionto Ambient o TSSOP-24 θ 78 C/W JA MLP-24 25 ESD Rating (HumanBodyModel) ED SD TV B k Note: This device is ESD sensitive. Use of standard ESD handling precautions is required. Electrical Characteristics o Unless specified: T = 25 C, V =16V, Fs=200kHz . 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The two channels of the controller capacitor) which is connected between the SS pin and operate at 180 degree out of phase from each other. ground. When the controller is enabled (by pulling EN Since input currents are interleaved in a two-phase pin high), one internal 84uA current source, I (soft SS, converter, input ripple current is lower and smaller input start current) will charge the soft-start capacitor capacitance can be used for filtering. Also, with lower gradually. The PWM output starts pulsing when the inductor current and smaller inductor ripple current per soft start voltage reaches 1V. 2 phase, overall I R losses are reduced. This soft start scheme will ensure the duty cycle to F F F F Freq req req req requency Se uency Se uency Se uency Se uency Setting tting tting tting tting increase slowly, therefore limiting the charging current into the output capacitor and also ensuring the The frequency of the SC2545 is user- programmable. inductor does not saturate. The soft start capacitor The oscillator of SC2545 can be programmed with an will eventually be charged up to 2.5V. external resistor from the Rosc pin to the ground. The step-down controller is capable of operating up to 300kHz. The relationship between oscillation frequency The soft-start sequence is initiated when EN pin is high and Vcc >4.5V or during recovery from a fault condition versus oscillation resistor is shown in Figure 1. ( OCP, OVP, or UVLO). The advantages of using constant frequency operation The period of start up can be programed by the soft are simple passive component selection and ease of start capacitor: feedback compensation. Before setting the operating frequency, the following trade-offs should be considered. Css × 2.5V Tss = 1) Passive component size 84µA 2) Circuitry efficiency By tieing the two soft start pins together, the two 3) EMI condition output rails track each other at start up till the rail with 4) Minimum switch on time lower set level reaching regulation. Please refer the 5) Maximum duty ratio waveform on page 20. For a given output power, the sizes of the passive Shutdown Shutdown Shutdown Shutdown Shutdown components are inversely proportional to the switching frequency, whereas MOSFETs/Diodes switching losses When the EN pin is pulled low, an internal 15uA current are proportional to the operating frequency. Other issues source discharges the soft-start capacitor and DRVH/ such as heat dissipation, packaging and cost issues are DRVL signals stop pulsing. The output voltage ramps also to be considered. The frequency bands for signal down at a rate determined by the load condition. transmission should be avoided because of EM interference. The SC2545 can also be shutdown by pulling down directly on the SS pin. The designer needs to consider the slope of the SS pin voltage and choose a suitable 350 pull down resistor to prevent the output from 300 undershooting. 250 Shutdown can also be triggered when an OCP condition 200 occurs. When an OCP condition is detected, DRVH and 150 DRVL will stop pulsing and enter a “tri-state shutdown” 100 with the output voltage ramping down at a rate deter- mined by the load condition. The internal 15uA current 50 source will begin discharging the soft-start capacitor and when the soft-start voltage reaches 0.65V, DRVL Rosc(KOHM) will go high. Figure 1. Switching frequency versus Rosc. © 2005 Semtech Corp. 8 www.semtech.com Fsw(KHz) SC2545 POWER MANAGEMENT Applications Information (Cont.) Over Current Protection (OCP) Over Current Protection (OCP) Over Current Protection (OCP) Over Current Protection (OCP) Over Current Protection (OCP) The inductor current is sensed by using the low side TG TG MOSFET R . After low side MOSFET is turned on, ds(on) the OCP comparator starts monitoring the voltage I I drop across the MOSFET. The OCP trip level is pro- L L grammed by the resistor from the ILIM pin to the phase node. There is an internal current source that flows out of the ILIM pin which will generate a voltage 10 100n 0nS S OC OCP A P Ac cti tiv ve e drop on the setting resistor. When the sum of the Blan Blank ki in ng g setting resistor voltage and the MOSFET drain to source voltage is less then zero, the OCP condition will Figure 3. OCP comparator timing chart. be flagged. This functionality is depicted in Figure 2. The following formula is used to set the OCP level U Under V nder Voltage Lock Out (UVL oltage Lock Out (UVLO) O) U U Under V nder V nder Voltage Lock Out (UVL oltage Lock Out (UVL oltage Lock Out (UVLO) O) O) 10µAR×= I ×R The UVLO circuitry monitors Vcc and the soft start ILIM L _PEAK DS() ON begins once Vcc ramps up above 4.5V. There is a built When OCP is tripped, both high side and low side in 200mV hysteresis for the UVLO ramp down MOSFETs will be turned off and this condition is threshold. The gate driver output will be in “tri-state” latched. At the same time, the soft start cap will be (both high side and low side MOSFET off) once Vcc discharged by the internal current source of 15uA. ramps down bellow 4.2V (typical), and the soft start When the Vss drops bellow 0.65V, the DRVL pin will go cap will be discharged by internal 15uA current sink. high again. Ov Ov Ov Ov Over V er V er V er V er Voltage Pr oltage Pr oltage Pr oltage Pr oltage Pro o o o ot t t t tection (O ection (O ection (O ection (O ection (OVP) VP) VP) VP) VP) To avoid switching noise during the phase node commutation, a 100nS blanking time is built in after The OVP circuitry monitors the feedback voltages, If the low side MOSFET is turned on, as shown in Fig. 3. either feedback voltage exceeds 0.89V, the OVP condition is registered. Under this condition, the DRVH pins will be pulled low, and the DRVL pins will be pulled high. This will create a “crow bar” condition for the VCC input power rail in case the high side MOSFET is failed 10uA short. The crow bar operation may trip the input supply DRVH to prevent the load from seeing more voltage. OUTPUT ILIM + OCP Out Power Good Output Power Good Output Power Good Output Power Good Output Power Good Output - DRVL The power good is an open collector output. The PWRGD pin is pulled low at start up if any of the two feedback voltages below 90% of its regulation level. The ramp down threshold of the signal is 80% of the Figure 2. Block diagram of over current regulation target. External pull up is required for the protection. PWRGD pin, and the pull up resistor should be chosen such that the pin does not sink more than 2mA when PWRGD is low. © 2005 Semtech Corp. 9 www.semtech.com �� % �� & �#� !�� &� �� ’#�(��"�#�� *88�2<=$��$�>��%,�� )#�(��"� #�� %�� *#�!��"� #�� % �#�+��,(�� *88�2<=�� -#�.�� /#�0�� 1#��2 �#��&�� %��%�� %�� ?��"��#�� & �� !��&�0 ��0 �� 3.��!�� !��"��2%��%��2#&�3� �� %�� (��&�� 3.�� (��&�� #�.��&�� (��"��2%��%��2#&�3� � ��’�-��2�� 4��"��#��&�� ,�5��&�� (��"��#��&�� "�6��# �� .��&� �� 7��%��.)-�-�� %��"..,# �� 6��3.�� 7�� 2�� .��3.�� .��"��5��#�� .�� 2%��%��2�� %��)89��*89�� "��2%��%��2# ��:� $�� !�� "�#$�� 2�� "’;��6)#:!� �� $��$ � �� ,�� SC2545 POWER MANAGEMENT Applications Information (Cont.) The voltage rating of aluminum capacitors should be at The first term is the DC voltage across C at time t=0. o least 1.5V . The RMS current ripple rating should also The second term is the voltage variation caused by the o be greater than charge balance between the load and the converter δI o . output. The third term is voltage ripple due to ESL and 2 3 the fourth term is the voltage ripple due to ESR. The Usually it is necessary to have several capacitors of the total output voltage ripple is then a vector sum of the same type in parallel to satisfy the ESR requirement. last three terms. The voltage ripple caused by the capacitor charge/ discharge should be an order of magnitude smaller than Since the inductor current is a triangular waveform with the voltage ripple caused by the ESR. To guarantee this, peak-to-peak value *I , the ripple-voltage caused by δ o the capacitance should satisfy inductor current ripples is 10 C > . o 2πf R s esr δI o Δv ≈ , C In many applications, several low ESR ceramic 8C f o s capacitors are added in parallel with the aluminum capacitors in order to further reduce ESR and improve the ripple-voltage due to ESL is high frequency decoupling. Because the values of δI o capacitance and ESR are usually different in ceramic and Δv = L f , ESL esl s D aluminum capacitors, the following remarks are made to clarify some practical issues. and the ESR ripple-voltage is Remark 1: High frequency ceramic capacitors may not carry most of the ripple current. It also depends on Δv =R δI . ESR esr o the capacitor value. Only when the capacitor value is set properly, the effect of ceramic capacitor low ESR starts µ to be significant. For example, if a 10 F, 4m ceramic Ω Aluminum capacitors (e.g. electrolytic) have high µ capacitor is connected in parallel with 2x1500 F, capacitances and low ESLs. The ESR has the dominant 90m electrolytic capacitors, the ripple current in the Ω effect on the output ripple voltage. It is therefore very ceramic capacitor is only about 42% of the current in the important to minimize the ESR. Other types to choose µ electrolytic capacitors at the ripple frequency. If a 100 F, are solid OS-CON, POSCAP, and tantalum. 2m ceramic capacitor is used, the ripple current in Ω When determining the ESR value, both the steady state the ceramic capacitor will be about 4.2 times of that in ripple-voltage and the dynamic load transient need to be µ the electrolytic capacitors. When two 100 F, 2m Ω considered. To meet the steady state output ripple- ceramic capacitors are used, the current ratio increases voltage spec, the ESR should satisfy to 8.3. In this case most of the ripple current flows in the ceramic decoupling capacitor. The ESR of the ceramic ΔVO Re1 sr 〈 capacitors will then determine the output ripple-voltage. δIO To limit the dynamic output voltage overshoot/ Remark 2: The total equivalent capacitance of the filter undershoot within a (say 3%) of the steady state output bank is not simply the sum of all the paralleled capacitors. voltage from no load to full load, the ESR value should The total equivalent ESR is not simply the parallel satisfy combination of all the individual ESR’s either. Instead 3%VO they should be calculated using the following formula. Re2 sr 〈 IO 2 2 2 2 2 (R +R ) ω C C +(C +C ) 1a 1b 1a 1b 1a 1b Then, the required ESR value of the output capacitors C = eq(ω) 2 2 2 (R C +R C )ω C C +(C +C should be 1a 1a 1b 1b 1a 1b 1a 1b) R = min{R ,R }. esr esr1 esr2  2005 Semtech Corp. 11 www.semtech.com SC2545 POWER MANAGEMENT Applications Information (Cont.) 2 2 2 2 2 2 2 2 2 2 In Figure 6 the DC input voltage source has an internal R R R R ( (R R + + R R ) )ω ω C C C C + + ( (R R C C + + R R C C ) ) 1 1a a 1 1b b 1 1a a 1 1b b 1 1a a 1 1b b 1 1b b 1 1b b 1 1a a 1 1a a R R ( (ω ω) ) ::= = eq eq = = C Ceq eq( (ω ω) ) 2 2 2 2 2 2 2 2 2 2 impedance R and the input capacitor C has an ESR of in in ( (R R + + R R ) ) ω ω C C C C + + ( (C C + + C C ) ) 1 1a a 1 1b b 1 1a a 1 1b b 1 1a a 1 1b b R . MOSFET and input capacitor current waveforms, ESR esr voltage ripple and input voltage ripple are shown in Figure where R and C are the ESR and capacitance of 1a 1a 7. electrolytic capacitors, and R and C are the ESR and 1b 1b capacitance of the ceramic capacitors, respectively (Figure 5). i i Q1 Q1 C1a C1b Ceq i i Cin Cin R1a R1b Req V Ves esr r Figure 5. Equivalent RC branch. V VCin Cin Req and Ceq are both functions of frequency. For rigorous design, the equivalent ESR should be evaluated at the ripple frequency for voltage ripple calculation when both Figure 7. Typical waveforms at converter input. ceramic and electrolytic capacitors are used. If R = R 1a 1b = R and C = C = C , then R and C will be frequency- 1 1a 1b 1 eq eq It can be seen that the current in the input capacitor independent and pulses with high di/dt. Capacitors with low ESL should be used. It is also important to place the input capacitor R = 1/2 R and C = 2C . eq 1 eq 1 close to the MOSFETs on the PC board to reduce trace inductances around the pulse current loop. Input Capacitor (Cin) Input Capacitor (Cin) Input Capacitor (Cin) Input Capacitor (Cin) Input Capacitor (Cin) The RMS value of the capacitor current is approximately The input supply to the converter usually comes from a pre-regulator. Since the input supply is not ideal, input 2 δ D D 2 I = I D[(1+ )(1− ) + (1− D)]. capacitors are needed to filter the current pulses at the Cin o 2 12 η η switching frequency. A simple buck converter is shown in The power dissipated in the input capacitors is then Figure 6. 2 P = I R . Cin Cin esr 2 1 L1 For reliable operation, the maximum power dissipation o in the capacitors should not result in more than 10 C of Q1 temperature rise. Many manufacturers specify the maximum allowable ripple current (ARMS) rating of the Rin Resr capacitor at a given ripple frequency and ambient D1 Co Ro temperature. The input capacitance should be high enough to handle the ripple current. It is common pratice Cin VDC that multiple capacitors are placed in parallel to increase the ripple current handling capability. Figure 6. A simple model for the converter input. © 2005 Semtech Corp. 12 www.semtech.com 1 2 �� +��+3��$4�� +3��$�� +3��$4�� 1� 2�� 1� 2��#��5�� +3��$4�� $�� 1�3+2� �� $��3+�� )� � � �� ! ��"�� #�� "�� $��!%&’& ��()*��#��"�� !%&’&�� +��"�� ,�� -!�� -!��$��"�� )��+�� "�� $��3+� $�� "��#��"��+3��$4��"�� .��!��(�� 6��"�� !��%�"��- ��- ��# ��# �� "�� +3��$��#�� #��- /*�&��- /*�&�� +3��$��"�� +3��$��"�� $��"�� #��- 0*�&��1- �*�&2�/�- /*�&�� "��7�� +3��$4�� +3��$4�� "�� #��- 0*�&��- �/�1- �*�&2�/�*�&�� +3��$�� 2�� 8 �� "2�� 8�� #��- 0*�&��- �0�*�&�� 2�� SC2545 POWER MANAGEMENT Applications Information (Cont.) In Figure 9, Q is the gate charge needed to bring the T T T T Top Switc op Switc op Switc op Switc op Switch h h h h gs1 gate-to-source voltage V to the threshold voltage V . The RMS value of the top switch current is calculated as gs gs_th Q is the additional gate charge required for the switch gs2 current to reach its full-scale value I , and Q is the ds gd . charge needed to charge gate-to-drain (Miller) capacitance The conduction losses are then when V is falling. ds 2 P = I R . Switching losses occur during the time interval [t , t ]. tc Q1,rms ds(on) 1 3 Defining t = t -t and t can be approximated as r 3 1 r (Q + Q )R gs2 gd gt R varies with temperature and gate-source voltage. t = . ds(on) r V − V cc gsp Curves showing R variations can be found in ds(on) manufacturers’ data sheet. From the Si4860 datasheet, where R is the total resistance from the driver supply gt R is less than 8m when V is greater than 10V. Ω rail to the gate of the MOSFET. It includes the gate driver ds(on) gs However R increases by 50% as the junction internal impedance R , external resistance R and the ds(on) gi ge o o temperature increases from 25 C to 110 C. gate resistance R within the MOSFET : g The switching losses can be estimated using the simple R = R +R +R . gt gi ge g formula V is the Miller plateau voltage shown in Figure 9. 1 δ gsp P = (t + t )(1+ )I V f . ts r f o in s 2 2 Similarly an approximate expression for t is f where t is the rise time and t is the fall time of the r f (Q + Q )R switching process. Different manufactures have different gs2 gd gt t = . f definitions and test conditions for t and t . To clarify V gsp r f these, we sketch the typical MOSFET switching characteristics under clamped inductive mode in Figure Only a portion of the total losses P = Q V f is dissipated g g cc s 9. in the MOSFET package. Here Q is the total gate charge g specified in the datasheet. The power dissipated within Vd Vds s the MOSFET package is Vo Vol lt ts s Id Ids s M Mi il ll ler er pl plate atea au u R g P = Q V f . tg g cc s Vg Vgs s R gt Vg Vgs s th th The total power loss of the top switch is then P = P +P +P . t tc ts tg Qg Qgs s1 1 Qg Qgs s2 2 Qg Qgd d If the input supply of the power converter varies over a G Ga at te e charge charge t0 t0 t1 t1 t t2 2 t t3 3 wide range, then it will be necessary to weigh the relative importance of conduction and switching losses. Figure 9. MOSFET switching characteristics This is because conduction losses are inversely propor- tional to the input voltage. Switching loss however increases with the input voltage. The total power loss of MOSFET should be calculated and compared for high-line and low-line cases. The worst case is then used for thermal design. © 2005 Semtech Corp. 14 www.semtech.com �� +��(��* �� ( ��.�� )1��(�� %�� * ��(� �� .�� #2�� .�� 1$&3&�� %��4��* �� %��51�� !�� " �#$"%�" �#�&"’%��(��)�� 51��4�� (��!#*)’%�� .�� -�� +�� +��(�� (6 )��*�� ,�%��(�� -��.(�� (�� (�� /��* �� 0� � � �� #2��9��.�� ,� ��" �� %�"�� .��%��.� �� %��+�� (��(�� -��7��!� %��(�#$& 1’ �� (��)1� ��% ��-��*�� -��%��/��/%�� +��7�� ##��/�� ! ’��( � �� (6 �� %��.� �� %��%�� (%��.��%�� !��’��8�� (�� (�� #�� ,�� 8�� !��!��"��#�� ,��3 ��!�� $��"��%� �� &�’��(��%��&� �)��(��$�� *+,�"��$�� ./0�� +1�/2/� �� 3 &�(��4�� !��51��467 �� &�(��+�� $�� 9��9��$��#��!�� $��:1�� &8(��;��*+,�"��"� &2(��<� �� $�� $�� &/(��4��"��"�� /�9��$�� &=(��4��"��"�� -�� $�� #�7��1#:�� $�� 1�� %��&��*��&��’ 5��$��+��&’��-��%�� +��&��*��/ ��3��,��$�� +��%�� %�� $��&�� 8��3��%�� 6��/9:;� �� !�"#$��%��!�"#$�� &�� ’��&��(�)�� *�� +��&�%&�� ,��-��+��&�*��.�� !�"#$�� &��/��-��%%�� &��+��&�� *� ��+��&�� #��&�� *��&�� *��(*��*�� &�� *��0�� %��1,�2��3�0 ��*��!�"#$�� %��%��2��*� ��/��4��*�� %��3�0��%� 4�56��6��*��&��$��&�� !�"#$7��$�� &�� 3��*�� (0�$��36�� "! ! "#"# $$ !% �� %! !#!# !!!! !!!! % �� !�"�#$�!��% � � �� & �� & � �� & �� ’�� ( )�� *�!��%+� �� ,�� ’� )��-��.�,�� /��/��/� +�� +� �� 0�� 0�� 0�� 0�� & � �� 0�� &&�� &0�� 1� )�� )��2��’ �� SC2545 POWER MANAGEMENT Typical Characteristics CH1:Vi CH1: TG1 CH2: BG1 CH2:Ven CH3: TG2 CH3:VSS CH4: BG2 CH4:Vo Shut down by pulling down EN pin Gate waveform voltage. CH1:TG CH2:BG CH3:Vo CH3:VSS CH4:Io CH4:Vo Start up. Transient response(0-5A). CH1:TG CH2:BG CH3:TG Vs Vss s CH4:BG Vo1 Vo1 Vo2 Vo2 Over current protection (5A/10mV) “Peel off “Start up tracking by tieing SS1 and SS2 together. © 2005 Semtech Corp. 20 www.semtech.com 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 SC2545 POWER MANAGEMENT Typical Characteristics (Cont.) Vin=8V Vin=16V 190 100% 188 80% 186 60% 184 182 40% 180 20% 178 0% -40 -10 20 50 80 110 0 1234 567 89 10 Temperature (Degree C) Io(A) Efficiency Curve for Vout=3.3V. Freq. vs. Temp. ( Rosc=75kohm, Vin=16V). 350 10.5 300 10.3 250 10.1 200 9.9 150 9.7 100 9.5 50 10 12 14 16 18 20 22 24 26 28 30 Vin (V) Rosc(KOHM) Operating frequency vs. Rosc. Vcc vs. Vin ( Ta=25 Degree C). 9 10.13 8 10.11 7 10.09 6 10.07 5 10.05 10.03 4 -40 -20 0 20406080 100 120 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 Tj (Degree C) RILIM(KOHM) RILIM vs. OCP (Vi=12V). Vcc vs. Temp. © 2005 Semtech Corp. 21 www.semtech.com Efficient Fsw(KHz) Io(A) Vcc (V) Vcc (V) Fs (khz) SC2545 POWER MANAGEMENT Typical Characteristics (Cont.) 7.0 6.5 6.0 5.5 5.0 8 10 121416 18202224 26 28 Vin(V) Icc vs. Vin (25 DegreeC). 500 480 460 440 420 400 -40 -20 0 20406080 100 120 Tj (Degree C) DL min Ton vs. Tj (Vin=16V). 100 80 60 40 20 0 -40 -20 0 20 406080 100 120 Tj (Degree C) Dead time vs. Tj (Vin=16V, DH falling to DL rising). © 2005 Semtech Corp. 22 www.semtech.com Dead time (nS) Icc (mA) DRVL min Ton(nS) SC2545 POWER MANAGEMENT Outline Drawing - TSSOP-24 DIMENSIONS A INCHES MILLIMETERS DIM D e MIN NOM MAX MIN NOM MAX - - - - N A .047 1.20 .002 - .006 0.05 - 0.15 A1 A2 .031 - .042 0.80 - 1.05 2X E/2 b .007 - .012 0.19 - 0.30 c .003 - .007 0.09 - 0.20 E1 D .303 .307 .311 7.70 7.80 7.90 E E1 .169 .173 .177 4.30 4.40 4.50 PIN 1 INDICATOR E .252 BSC 6.40 BSC e .026 BSC 0.65 BSC L .018 .024 .030 0.45 0.60 0.75 (.039) (1.0) ccc C 1 2 3 L1 e/2 N 24 24 2X N/2 TIPS 01 0 - 8 0 - 8 B aaa .004 0.10 bbb .004 0.10 ccc .008 0.20 D aaa C A2 A SEATING PLANE H C A1 bxN c bbb C A-B D GAGE PLANE 0.25 L 01 (L1) DETAIL A SEE DETAIL A SIDE VIEW NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. DATUMS -A - AND -B - TO BE DETERMINED AT DATUM PLANE -H- 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. 4. REFERENCE JEDEC STD MO-153, VARIATION AD. Land Pattern - TSSOP-24 X DIMENSIONS DIM INCHES MILLIMETERS C (.222) (5.65) G .161 4.10 (C) G Z P .026 0.65 X .016 0.40 Y .061 1.55 Y Z .283 7.20 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 © 2005 Semtech Corp. 23 www.semtech.com SC2545 POWER MANAGEMENT Outline Drawing - MLPQ-24 (4 x 4mm) A D B DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX A .031 .035 .040 0.80 0.90 1.00 A1 .000 .001 .002 0.00 0.02 0.05 - - - - A2 (.008) (0.20) PIN 1 b .007 .010 .012 0.18 0.25 0.30 E INDICATOR D .151 .157 .163 3.85 4.00 4.15 Top View (LASER MARK) D1 .100 .106 .110 2.55 2.70 2.80 E .151 .157 .163 3.85 4.00 4.15 E1 .100 2.70 2.80 .106 .110 2.55 e .020 BSC 0.50 BSC L .011 .016 .020 0.30 0.40 0.50 N 24 24 aaa .004 0.10 A2 bbb .004 0.10 A SEATING aaa C PLANE A1 C D1 LxN E/2 E1 Bottom View 2 1 N bxN bbb C A B e D/2 NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 2. Land Pattern - MLPQ-24 (4 x 4mm) K DIMENSIONS DIM INCHES MILLIMETERS (.155) (3.95) C G .122 3.10 H .106 2.70 G Z (C) H K .106 2.70 P .021 0.50 X .010 0.25 Y .033 0.85 Z .189 4.80 X P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 © 2005 Semtech Corp. 24 www.semtech.com

Frequently asked questions

At GID Industrial (Elite.Parts' parent company), we specialize in procuring industrial parts. We know where to find the rare and obsolete equipment that our customers need in order to get back to business. There are other companies who claim to do what we do, but we're confident that our commitment to quality and value is unparalleled in our field.

Warranties differ by part and by which suppliers we use to procure it for you. Sometimes, a part will be sold as-is and without a warranty. Our specialty, single board computers, tend to receive a one-year warranty.

Elite.Parts can ship via FedEx, UPS, DHL, and USPS. We have accounts with each of them and generally ship using one of those, but we can also ship using your account if you would prefer. However, we can use other carriers if it will be more convenient for you.

Absolutely! We are happy to serve customers regardless of location. We work with international clients all the time, and we are familiar with shipping to destinations all across the globe.

All major credit cards are accepted: Visa, MasterCard, Discover, and American Express. We will also accept payment made with wire transfer or PayPal. Checks will only be accepted from customers in the USA. Terms may available for larger orders, upon approval.

What they say about us

FANTASTIC RESOURCE

One of our top priorities is maintaining our business with precision, and we are constantly looking for affiliates that can help us achieve our goal. With the aid of GID Industrial, our obsolete product management has never been more efficient. They have been a great resource to our company, and have quickly become a go-to supplier on our list!

Bucher Emhart Glass

EXCELLENT SERVICE

With our strict fundamentals and high expectations, we were surprised when we came across GID Industrial and their competitive pricing. When we approached them with our issue, they were incredibly confident in being able to provide us with a seamless solution at the best price for us. GID Industrial quickly understood our needs and provided us with excellent service, as well as fully tested product to ensure what we received would be the right fit for our company.

Fuji

HARD TO FIND A BETTER PROVIDER

Our company provides services to aid in the manufacture of technological products, such as semiconductors and flat panel displays, and often searching for distributors of obsolete product we require can waste time and money. Finding GID Industrial proved to be a great asset to our company, with cost effective solutions and superior knowledge on all of their materials, it’d be hard to find a better provider of obsolete or hard to find products.

Applied Materials

CONSISTENTLY DELIVERS QUALITY SOLUTIONS

Over the years, the equipment used in our company becomes discontinued, but they’re still of great use to us and our customers. Once these products are no longer available through the manufacturer, finding a reliable, quick supplier is a necessity, and luckily for us, GID Industrial has provided the most trustworthy, quality solutions to our obsolete component needs.

Nidec Vamco

TERRIFIC RESOURCE

This company has been a terrific help to us (I work for Trican Well Service) in sourcing the Micron Ram Memory we needed for our Siemens computers. Great service! And great pricing! I know when the product is shipping and when it will arrive, all the way through the ordering process.

Trican Well Service

GO TO SOURCE

When I can't find an obsolete part, I first call GID and they'll come up with my parts every time. Great customer service and follow up as well. Scott emails me from time to time to touch base and see if we're having trouble finding something.....which is often with our 25 yr old equipment.

ConAgra Foods

SEMTECH SC2545

Why buy from GID?

What they say about us

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